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gepardcv

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Posts posted by gepardcv

  1. 19 hours ago, TMoney said:

    What the hell am I watching?

    Who and what is this thing for? Why would I want one?

    I'll give them credit though, they really went for it. No Oculus ripoff here.

    If you mean the Mac Pro, I have no idea. Most people who want that kind of compute power either DIY their own boxes or rent by the hour from Amazon. I guess if Mac OS is a requirement along with massive computational power it kinda makes sense, but that’s uncommon. Maybe for running proprietary hedge fund code.

    If you mean the Vision Pro, I’d find it very handy as a replacement for a bunch of external screens. It seems capable of displaying remote desktops. I could use a much smaller desk if I didn’t have to put a 27-30” screen on it. Or I would just pile my desk with even more audio hardware. 🙃

  2. @tonyxu: Maybe try emailing Bottlehead? It’s local to you. Although it has in-house expertise to do the work, I doubt anyone there will take on this project. That said, the company has been around the Seattle area for many years and might share some contacts. 
     

    Meanwhile, for safety, please unplug the amp and close the case. The voltages on some of the wires and traces inside are very dangerous (and who knows if that build is safely grounded at all).

  3. I would appreciate a bit of advice with regard to mounting non-isolated active devices on heatsinks.

    While trying to get my feet wet with speaker amps, I bought a Gainclone kit (LM3886-based chipamp). The active devices included all require heatsink mounting, and all are non-isolated (LM3886T in particular instead of the isolated 3886TF). The kit does not include isolation pads, PEEK screws, shoulder washers, or any of the things we use here to attach high-voltage devices. I asked the vendor about this, and he said that I shouldn’t worry about it — he said that the tabs are grounded, and therefore do not need to be isolated from the chassis. I don’t understand this statement, and asked if “grounded” in this case means “the case is connected to safety earth on the inlet”, and if that implies that the amp cannot ever be connected to an outlet without a safety earth line (which I normally think of as necessary to protect against accidental shorts, but not as a hard requirement to prevent electrocution in everyday operation). He replied: “The power supply uses a UL Listed transformer, power entrance, fuse block, and power switch.”

    This does not sit well with me, but before I push back on the vendor, I thought I’d ask here if I’m just ignorant. Is there something about UL Listed hardware that prevents a high-voltage device which is electrically common with the amplifier case from shocking the user? Is there a grounding scheme that negates this danger?

  4. I thought that tying two secondary windings together to make a center tap effectively creates a series AC circuit, which adds together the voltages of the windings. So two 12V secondary windings make a 24V center-tapped winding. And 18+18 would turn into 36-0-36, which definitely seems too high for a 20V DC output. Is that wrong?

  5. Question about transformers. I have a GRLV I want to repurpose, and it’s been used with a 22VCT transformer (single bridge rectifier) which for various reasons can’t be reused. I want to use the GRLV now with an Antek dual secondary transformer. I don’t want to change the bridges on the GRLV because it’s one of the earlier PCB versions that has incorrectly sized holes on the rectifier pads and it’s annoying and messy to (un)solder all that.

    1. Can I tie the secondaries together and achieve a center-tapped equivalent? This suggests that I can: https://electronics.stackexchange.com/a/571731/59134

    2. There is no 11V dual secondary Antek product, but there’s a 12V (https://www.antekinc.com/as-0512-50va-12v-transformer/). This means it’ll be equivalent to 24VCT (if I understand things correctly). Is that okay for a 20V output GRLV, or too high?

    I guess I could spring for a custom 22VCT transformer, but Anteks are so much cheaper and more convenient to buy.

  6. Well, two years later, I'm thinking about finally finishing up a Mini Dynalo build. Last time I was working on it, I stuffed the boards but failed to solder the on-board regulators (even though I used a stencil with solder paste, I still suck at such fine hot air work). I picked up the AMB sigma78 and sigma79s, and noticed they mismatch the U5 and U7 areas on the PCB. U5 and U7 have holes for 5 pins, but the regulators have 3. It looks from photos others have posted that the outside pins are ignored. What's up with the extra holes on the board?

    • Like 1
  7. You need to look at the software you use (DJing sounds like you need some pro audio support) and make sure it works natively on Apple’s new CPUs, or at least through Rosetta2 binary translation. If it is not supported for any reason, buy a MBP now while you can still get one with an Intel CPU.

    If you’re good with Apple Silicon, then definitely hold off on buying a MBP. If rumors are to be believed, a refresh will come soon (this fall, so within a few months) and will bring a new form factor. Supposedly, it’ll get rid of the idiotic Touch Bar on the keyboards, bring back MagSafe power connectors, and bring back extra ports.

    As far as typing comfort goes, just buy a nice external keyboard. I rather like Keychron keyboards, for example. Battery life and power management sucks compared to Apple external keyboards, but the typing feel is massively better.

  8. Wait! Does this mean Audeze finally managed to make a headphone that doesn't make violins sound like violas?!

    @Beefy: Re: “electrostats seem to have stood completely still, while planars and dynamics have come forward in leaps and bounds” — my observations from attending numerous (large) meets for several years before covid have been that no TOTL planar or dynamic beats my SR-007 (v2.5 I guess?) and Carbon combo. Not the Utopia, not the LCD-4, not the piece of shit Abyss, nothing Hifiman (haven't heard their $6k thing though), not the Meze Empyrean (though that thing is pure catnip for bassheads). They're nice, sure, and most have the advantage of not needing much of a specialized amp. But they're not nicer than the current-production 007 or the 1993 SR-Omega (which I don't have, alas, but have had the fortune to try once).

    This opinion is unpopular on other forums. 🤷🏻‍♂️

    Maybe this means there's a (local?) maximum in headphone quality, and various manufacturers are slowly reaching it.

    @spritzer: What amps do you think the measurements are coming from?

    • Like 3
  9. @ShortBtwnHdset: Don't let Pars scare you away. :) No build guides doesn't mean you won't get answers.

    The Dynalo is easy. That kit you bought looks pretty good, assuming the MPSW parts really are genuine and matched as advertised. Look at BOMs, but above all follow the silkscreen on the boards. Stuff the boards. Check the GRLV board you have for the type of transformer secondary windings you'll need, whether center-tapped or not (there are a couple of different GRLV versions floating around). I used an Antek 50VA 22V for a Dynalo, it worked great, but might not be right for your GRLV board. This thread will have more info.

    Do you know how to safely wire up mains? That'll be the next challenge. It's also not difficult, but needs to be done carefully and correctly.

    While the wiring is pretty self-explanatory, you'll also need to ground the amp correctly to avoid noise. Again, there's info in various threads (including the KGSSHV thread), and feel free to ask when you get that far.

    • Like 2
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